UBC Theses and Dissertations
Phospocreatine resynthesis after exercise and hypoxia in the carp (cyprinus carpio) : a 31P-NMRS study Hallman, Troy M.
Phosphocreatine (PCr) was reduced in carp muscle by exercise or hypoxia at 15°C and 25°C in order to assess the influence of pH and temperature in PCr synthesis in vivo. Intramuscular PCr levels and intracellular pH (pH,) values were determined by 31P-NMRS. Exercise resulted in a significantly more acidic pHi than following hypoxia, differing by 0.38 and 0.44 pH units at 15°C and 25°C, respectively. The lower pH values in exercised carp slowed the recovery of PCr compared with posthypoxic fish, requiring a four-fold increase in the amount of time necessary to rebuild PCr levels. Throughout the recovery period. PCr levels following hypoxia were consistently and significantly higher than those following exercise. Intracellular pH continued to fall for up to over two hours, dropping to less than 6.3 and 6.7 following exercise and hypoxia, respectively. This continuing decline in pHi was correlated with the rise in PCr levels up to the time when PCr was nearly recovered. During hypoxia, 25°C acclimated carp depleted PCr stores more quickly than those at 15°C, temperature had no effect on the time for recovery of either PCr or pHi.
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